Cybersecurity

Botnet

Definition

A botnet is a network of private computers infected with malicious software and controlled as a group without the owners' knowledge, e.g., to send spam or launch DDoS attacks.

Why It Matters

Botnets are the massive, distributed engines that power many large-scale cyberattacks. By controlling thousands or even millions of compromised machines, attackers can amplify their impact significantly.

Contextual Example

An attacker uses a botnet of 100,000 compromised home routers and IoT devices to launch a massive DDoS attack against a bank, overwhelming its servers and taking its website offline.

Common Misunderstandings

  • The individual infected machines are known as "bots" or "zombies".
  • The attacker controls the botnet through a "command and control" (C&C) server.

Related Terms

Last Updated: December 17, 2025